Lounges make trips more tolerable but do they make trips fun?
I do admit on trips I look forward to trying out a lounge or the business class product of certain airlines or new aircraft.
But the trip itself is the main focus. A bad flight shouldn’t ruin the trip.
I didn’t fly much on business so the vast majority of flights I’ve taken over the years have been for leisure and all paid for by me, mostly international trips too.
I might feel the burnout that the OP describes if I flew a lot for business and most of it was domestic.
You have a work vs. pleasure dichotomy there. And planes on international flights tend to be nicer than those for domestic flights, though obviously they’re longer flights, which can wear you down.
I might have enjoyed trips and flights paid for by my employer but the novelty would wear off if it was constant travel like those characters in the Up in the Air movie. Though of course having a ton of points would be nice.